1. Field of the Invention
The present invention relates to a mechanism for applying a positioning force between upper and lower jawbone, with the mechanism including an outer telescopic element and an inner telescopic element displaceable within the outer telescopic element, and with the outer and inner telescopic elements having each an eyelet for connection to a teeth brace.
2. Description of the Prior Art
Mechanisms of the above-described type, such as, e.g., disclosed in U.S. Pat. No. 4,551,095 or in European publication EP-O 128 744-B1, serve for moving the low jawbone relative to the outer jawbone anteriorly or posteriorly. Such mechanisms are being used more and more in orthodontic applications. These mechanisms include double plates, Herbst hinges or other bimaxillar mechanisms. The essential requirement these mechanisms should meet consists in that they should provide for an individual stepwise positioning of the low jawbone relative to the upper jawbone by using two telescopic elements displaceable relative to each other.
In the known mechanisms, an inner telescopic element is displaced in a hollow outer element, with both elements being attached to teeth braces of the lower and upper jawbones. The drawback of these mechanisms consists in that the two elements can separate from each other. Such separation leads to that the mechanisms cannot function properly and can result in injury of the inner cheek of a patient.
Accordingly, an object of the present invention is to provide a mechanism of the above-described type in which a danger of separation of the two telescopic elements is eliminated.
Another object of the present invention is to provide a mechanism of the above-described type which would insure an adaptation of the mechanism to the individual low jawbone position of a patient before installation of the mechanism in place.